It is a stunning turnabout. A party that once spoke with urgency and apparent conviction about the importance of ethical leadership — fidelity, honesty, honor, decency, good manners, setting a good example — has hitched its wagon to the most thoroughly and comprehensively corrupt individual who has ever been elected president. Some of the men who have been elected president have been unscrupulous in certain areas — infidelity, lying, dirty tricks, financial misdeeds — but we’ve never before had the full-spectrum corruption we see in the life of Donald Trump.

.. And the moral indictment against Mr. Trump is obvious and overwhelming. Corruption has been evident in Mr. Trump’s private and public life,

in how he has treated his wives,

in his business dealings and scams,

in his pathological lying and cruelty,

in his bullying and shamelessness,

in his conspiracy-mongering and appeals to the darkest impulses of Americans. (Senator Bob Corker, a Republican, refers to the president’s race-based comments as a “base stimulator.”)

Mr. Trump’s corruptions are ingrained, the result of a lifetime of habits. It was delusional to think he would change for the better once he became president.

.. Some of us who have been lifelong Republicans and previously served in Republican administrations held out a faint hope that our party would at some point say “Enough!”; that there would be some line Mr. Trump would cross, some boundary he would transgress, some norm he would shatter, some civic guardrail he would uproot, some action he would take, some scheme or scandal he would be involved in that would cause large numbers of Republicans to break with the president. No such luck. Mr. Trump’s corruptions have therefore become theirs. So far there’s been no bottom, and there may never be.

.. the Republican Party’s as-yet unbreakable attachment to Mr. Trump is coming at quite a cost. There is the rank hypocrisy, the squandered ability to venerate public character or criticize Democrats who lack it, and the damage to the white Evangelical movement, which has for the most part enthusiastically rallied to Mr. Trump and as a result has been largely discredited.

.. Mr. Trump and the Republican Party are right now the chief emblem of corruption and cynicism in American political life, of an ethic of might makes right. Dehumanizing others is fashionable and truth is relative. (“Truth isn’t truth,” in the infamous words of Mr. Trump’s lawyer Rudy Giuliani.) They are stripping politics of its high purpose and nobility.

.. A warning to my Republican friends: The worst is yet to come. Thanks to the work of Robert Mueller — a distinguished public servant, not the leader of a “group of Angry Democrat Thugs” — we are going to discover deeper and deeper layers to Mr. Trump’s corruption. When we do, I expect Mr. Trump will unravel further as he feels more cornered, more desperate, more enraged; his behavior will become ever more erratic, disordered and crazed.

Most Republicans, having thrown their MAGA hats over the Trump wall, will stay with him until the end. Was a tax cut, deregulation and court appointments really worth all this?